1890.] 



on Electromagnetic Badiation. 



83 



of an electric oscillator. The dotted line shows the electric force at 

 various points, and the continuous line the magnetic force. In the 

 first diagram the magnetic force is at its maximum near the origin, 

 while the electric force there is zero. In the second the magnetic 

 energy near the origin has partly turned into electric energy, and 

 consequently electric force begins. The succeeding figures show 

 how the magnetic force decreases near the origin, while the electric 

 force grows and the waves already thrown off spread away. The 

 change of magnetic force between Figures 4 and 5 is so rapid, 



that a few dashed lines, showing interpolated positions, are introduced 

 to show how it proceeds. It will be observed how a hollow comes in 

 the line showing electric force, which gradually increases, and, cross- 

 ing the line of zero force at about a quarter of a wave-length from 

 the origin, is the source of the electric wave, which, starting with this 

 odds, picks up and remains thenceforward coincident with the mag- 

 netic wave. From this origin of electric waves they spread out along 

 with the magnetic waves and in towards the origin, to be reproduced 

 again from this point on the next vibration. These electric and 



G 2 



